Semi-automatic firearms, such as rifles and shotguns, are designed to fire a round of ammunition, such as a cartridge or shotshell, in response to each squeeze of the trigger of the firearm, and thereafter automatically load the next shell or cartridge from the firearm magazine into the chamber of the firearm. During firing, the primer of the round of ammunition ignites the propellant (powder) inside the round, producing an expanding column of high pressure gases within the chamber and barrel of the firearm. The force of this expanding gas propels the bullet/shot of the cartridge or shell down the barrel.
In standard auto loading rifles, the addition of a silencer or suppressor to the muzzle of the weapon generates an increase in operating energy, causing the rifle to cycle faster than it would normally cycle if the suppressor were not installed. In known systems, the operator manually switches a gas regulating device to modify the operating characteristics of the weapon to compensate for this increased cyclic rate. This manual switch will typically have a lever or rotational plug that requires the operator to manually switch the system from one setting to the other. In a manually switched gas system, gases are either diverted (bled off) or restricted in order to reduce the overall energy available to operate the firearm.